Switch control system



April 2, 1940. c.w DALZELL SWITCH CONTROL SYSTEM Filed Aug. 12, 1959 INVENTOR Clare HIS ATTORNEY a m w N 13 Ex- Patented Apr. 3, 1940 PATENT OFFICE SWITCH CONTROL SYSTEM Clarence W. D-alzell, Belleville, N. 3., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application August 12,

8 Claims.

, My invention relates to switch control systems for railway track switches, and has particular reference to improved systems of the class in which a railway track switch is remotely controlled through the medium of a switch control lever. I

In systems .of theabove class, switch control levers movable between a normal and a reverse position are provided to effect movement of a 1 switch or switches to corresponding positions.

Control of each switch is established by its associated lever usually through the medium of a polarized relay. The polarized relay usually is connected in circuit with two wires supplied with current of one polarity or the other in accordance with the position .of the lever to control the polarized relay to one or the other of its positions, thereby causing the relay to repeat the position of the lever.

The polarized relay is employed to establish selective control of a switch operating mechanism in accordance with the relative position of the switch with respect to the relay. When the relay and switch are out of corr spondence, control of the associated switch operating mechanism is established by a circuit or circuits in such manner that the switch is caused to be operated to its position of correspondence with the relay, and since the relaynormally repeats the position of the lever, the switch normally is. operated to its position of correspondence with the lever.

The polarized relay above mentioned normally is positioned adjacent its associated switch, and consequently 'is. subject to comparatively. severe vibrations and shocks due to trains traveling over or adjacent the switch. Thus, in the event that the switch and lever are in agreement, the polarized relay might become open-circuited or deenergized due, for example, to an extreme jar severing or disconnecting one of its control wires. Under the above condition, the polarized armature of the relay might then be jarred or vibrated, since it is no longer held by the magnetic circuit of the relay to its position of correspondence with the switch, to a. position out of correspondence with the switch, thereby establishing control of the switch operating mechanism to cause the switch to move to its position of correspondence with the relay. If this happens when a train is passing over a switch, it is apparent that an unsafe condition is established, and the movement of the switch under the train might cause derailment of the train. Furthermore, with the switch unoccupied, a dangerous condition also is established due to the fact that the switch 1939, Serial 'No. 289,892 (o1. 246E242) and lever are out of correspondence and the lever is removed from control of the switch.

Accordingly, an object of my present invention is to provide improved systems of the class described and incorporating means to insure against improper operation of the switch in the event that the polarized relay and switch should accidentally be out of correspondence.

Another object is to provide improved systems of the class described which employs two switch operating relays each selectively responsive only to current of different polarities, and which incorporates means controlled by each relay for selectively controlling the switch.

A further object is to provide improved systems of the class described which employs two switch operatingrelays each arranged andconstructed in such manner that the associated'relay armature is picked up in response to the magnetic flux created by'current of the proper polarity but is held down by the magnetic flux created by current of. the improper polarity.

Another object is to provide improved systems of the class described and incorporating means controlled by the switch control lever for supplying current of one polarity or the other to each of the two switch operating relays.

A further object is to provide improved systems of the class described and incorporating novel and improved. means for at times preventing the switch control lever from supplying current to one or the other of the two switch operating relays 1 An additional object is to provide improved systems of the class described and incorporating novel and improved means for at times removing the switch control lever from control of one 01' the two switch operating relays until such time as control is established over the other of the two relays.

A further object is to provide improved switch control systems adapted for use with electric switch operating mechanisms.-

Another object is to provide improved switch control systems.

Other objects and advantages of my invention will be apparentv from the following description taken in connection with the accompanying drawing. 1

I shall describe two forms of apparatus embodying, my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawing, Fig- 1 is a diagrammatic view showing one form of apparatus. embodying my invention. Fig. 2 is a diagrammatic view of a modified form of the apparatus shown in Fig. 1, also embodying my invention.

Similar reference characters refer to similar parts in each of the two views.

Referring first to Fig. 1, the reference character W designates a railway track switch which is operated between a normal and a reverse position by means of a switch mechanism SM. Mechanism SM, as herein shown, is an electric switch movement having a reversible motor M shown comprising an armature winding 5 and a field winding 6, but it is contemplated that other types of switch movements may be employed such, for example, as an electro-pneumatic switch movement.

The reference character J designates a circuit controller operatively connected in the usual manner with switch W and switch mechanism SM. Controller J comprises a movable contact member I which engages a fixed contact member 3 at all positions of the switch except when the switch is in its full reverse position, and which movable member 1 also engages a second fixed contact member 9 at all positions of switch W except when the switch is in its full normal position.

The reference character E designates a manually operable two-position switch control lever, which may, for example, be a switch lever of an interlocking machine, and which is operable between a normal position N in which lever contacts Iii-l l and l2-l3 are closed, and a reverse position R in which lever contacts Ill-43 and |2-|4 are closed. In the mid position of lever E intermediate its normal and reverse positions, all contacts of lever E are open. Lever E is adapted to selectively control switch W to its normal or reverse position in accordance with the respective normal and reverse position of the lever, through the medium of control apparatus hereinafter referred to and including a normal switch operating relay NWR, a reverse switch operating relay RWR, and a polarized line relay WR.

Relay WR is connected in circuit with two line wires l5 and I6 extending from lever E to relay WR, which relay normally is positioned adjacent switch W. Current of normal or reverse polarity is supplied to wires [5 and I6 from a suitable source of current, such as a battery not shown in the drawing but having its two terminals designated by the reference characters B and C, according as lever E is in its normal or reverse position, the contacts of the lever functioning, as can readily be seen from an inspection'of Fig. 1, as a pole changer.

Normal switch operating relay NWR comprises a two-legged U-shaped core I! carrying a main winding IS. The two vertical legs 59a and I91) of core I! are each provided at their lower ends (as viewed in the drawing) with core extensions 20a. and 20b, respectively. These extensions extend underneath armature 21 of relay NWR and are engaged by the armature in its released position. The core extensions 20a and 2017 also carry auxiliary windings 22a and 22b, respectively. When main winding it of relay NWR is supplied with current and armature 2| is released, the main flux set up by such current threads the core extensions 20a and 20b and armature 2|, thereby holding the armature down in its released position. If, now, auxiliary windings 22a and 22b are supplied with current of the proper magnitude and polarity to set up a magnetic flux which opposes the main flux due to the current supplied to the main winding of the relay, the main flux of the relay then threads the air gap between the lower end of legs 19a and i911 of the core and armature 2|, with the result that the armature is attracted by such flux to its upper or picked up position. It can be seen from the foregoing that if the flux set up by the current supplied to the auxiliary windings 22a and 22b is in agreement with the flux set up by the ciu'rent in winding i8, then armature 2| is held attracted in its lower position. It follows, therefore, that relay NWR. is picked up when and only when the main winding of the relay is supplied with current of a proper polarity to set up a main flux opposing the flux set up by the current supplied to the auxiliary windings of the relay. The auxiliary windings of relay NWR are arranged in such manner that when supplied with current of a preselected polarity over a circuit which will be traced shortly, the flux created thereby opposes the flux created in the main winding of the relay only when the main winding is supplied with current corresponding to current of normal polarity in wires l5 and 56 connected to lever E. Relay N'WR, therefore, is responsive to current of but normal polarity.

The reverse switch operating relay RWR is similar to the normal switch operating relay NWR in all respects, except that it will respond only to current of reverse polarity supplied to its main winding when its auxiliary windings are energized.

The reference character NOR designates an overload relay having an overload winding 24 and a reset winding 25. Connected in parallel with overload winding 2 is a resistor 26, and the winding is provided with an armature 21 which is biased, as shown, by means of a toggle 28 to its last operated position.

Reset winding 25 also is provided with an armature 29 which at times engages armature 2! of the overload winding to operate that armature to its normal position, that is, the position illustrated in Fig. 1.

The operation of relay NOR is as follows. Normally, the parts of the relay are in the condition illustrated in Fig. 1. In this condition of the relay, overload winding 24 is deenergized, its armature 21 is held in its normal or lower position by virtue of the action of toggle 28, and

contact 38-3! associated with armature 21 is closed. Reset winding 25 also is deenergized, with the result that its armature 29 is released to open contact 32-33 associated therewith.

Armature 29 in its released position also is out of engagement with armature 21. Overload winding 24 and resistor 26 (which are connected in parallel) are so designed and proportioned that if current below a predetermined magnitude is applied to the circuit of the overload winding, the current divides between the resistor 26 and winding 24 in such manner that the energization of winding 24 is ineffective to operate armature 21 out of its normal position illustrated. However, in the event that current above the predetermined magnitude is applied across resistor 26 and winding 24, the increased current causes resistor 26 to heat up and thereby increase its resistance, with the result that'the energization of winding 24 is increased to a value which is sufficient to attract armature 21 to its upper or operated position against the action of toggle 28, thereby opening contact 3U-3l. Armature 2'! remains in its upper or operated, position by 24 is deeeer izedl Armatu e o rela NOB. s r storedoes n rma ees tien' rese w nd ng 5. Qt relay N93 is ene i ed medita s a m t re 29 o its attracted position. The movement of arma- We 29 wit t ated o it nta1 s s t o .sase arma ur Z an act te ha a m to itsnormal position past togglelli', thereby reclosing contact 30 -31 and restoring armature I It should be noted that with armature 21of overload wind ing 24 held in its normalaposition by virtue of toggle 2 armature 23 of reset winding 24, may be operated into its released or its attracted position according as reset winding 25 is deen- "ergized or energized, to open or close contact 32%; s. h ca e m e. i h u effecting operation of armature Z'Fofoverload winding 24.

The reference character R'OR designates'atoggle action overload relay, similar in all respects 'to relay NOR above described.

Having thus described the apparatus embodying my invention as illustrated in- Fig. 1, I shall now explain the operation and shall at the same time trace in detail the circuits controlling the various parts of the apparatus.

o I shall first assume that the apparatus is in its normal condition, as illustrated in Fig. 1. In this condition of the-apparatus, switch W is in its normal position an'd'lever E also is in its corresponding normal position. Relay WR is energized by current of what I shall term normal,

polaritysupplied from wires l5 and I6. Switch operating relays NWR' and RWR and overload relays NOR and ROR are deenergized. Motor M ofswitch mechanism SM also is deenergized. j

o In "order to operate switch W to its reverse position, lever E is first moved to itsvreverse position, thereby reversing the polarity of current supplied towires l5 and I6 and to relay with the result that polar contact member 35 of Q relay WR is shifted to its reverse position to close its] reverse polar contact 35-86. Main winding B of relay RWR now becomes energized over a circuit extending from terminal B through contact Ill-43 of leverE, wire l6, wire 39, re.-

1 *versepolar contact35-3 6 of relay'VVR, wire 40, main windinglfi of relay RWR, wire dl, reset winding of normal overload relay NOR, wire 42, contact 3l--30 ofoverload'winding 24 1: reverse overload relay ROR, wire 43, contact B-1 of; circuit controller J, wire 44, wire l5 and contact I 4-l2 of lever E to terminal C. 'I'he'ener- 'gization of main winding I 8 of relay RWR sets up a main flux in the relay core, whichas pointed .out previously, tends to hold armature ill of relay RWR in its released position. This holddown effect ofthe main flux is neutralized however, by the energization of the relay auxiliary windings 22a and'ZZb, which become energized over an obvious circuit passing from terminal B through auxiliary windings 22b and 22a of relay RWR, auxiliary windings 22b and 2a of relay N WR, and contact 32-33 of winding 25 of normal overloadrelay NOR to terminal 0; and as a resuit the armature of relay RWR is caused to be picked up. Relay RWR in picking up closes front contact efi46a, whereupon motor M of switch mechanism SM is energized by current of a polarity such as to cause the motor to operate and move switch W to its reverse position. A circuit for motor M may be traced from terminal B through field windin 6 of motor M, overload winding 24 of reverse overload relay RORand es stor '25 ,cqaneet d n parallel h rewimnorit Qn -45 o re a -RWR armatureIwindmo or M a heel; onta t "*flb of ing 5 relay NWR to terminal C. Operation of motor i maintained over the above circuit (unless the mot r e es v r a ed un i su time a the switch reaches its full reverse position, at

which position of the switch contact 7-8 of con-:-

tion in operating to its reverse position," and as a result motor M is overloaded and draws-excessive current, overload winding 24 of relay ROB. then becomes effective to operate its, armature 21 into its operated position, thereby opening contact 39 3i interposed in the previously traced circuit of the main winding of relay RvVR. With the main winding ofrelay RWR deenergized, its armature is released, and contact to interrupt the circuit previously traced for motor M, and further operation of the switch to its reverse position is terminated.

The switch may be restored to its normal position by moving lever E to its normal position.

wire 48, contact 3l of" overloadwinding '24 of normal overload relay NOR, wire 49, reset A winding 25 50, main winding l8 of relay NWR, wire 5!, normal polar contact 31 of relay NWR, wire -39, wire l6 and contactl3|2 of lever E to terminal C. When contact '32'-33 of reset winding "25'of' reverse overload relay ROR becomes closed,

auxiliary windings 22a and 22b of relay MNR of reverse overload relay ROR, wire deenergized, and opens its contact 3233 to;v deenergize the auxiliary winding of relay RWR. In the event that switch W strikes an obstruoe "ergized over a circuit which extends fromlterbecome energized over an obvious circuit which passes from terminal B through auxiliarywindings 22b and 22a of relay RWR, auxiliary windings 22b and 22a of relay NWR, and contact 32 -33 of reset winding 25 of relay ROR tote'r minal C, whereupon the armature of 'relayNWR ispicked up-and contact ll-41a of relaytNWR is closed. This completes an easily traced circuit which extendsfrom winding 6 of motor M, overload winding of normal overload relay NOR. with resistor 26 in parallel therewith, front contact 4l4la of relay NWR, armature winding 5 of'motor M, and back contact 46-461) of relay RWR to terminal C.

The polarity of energization of motor M is now such that motor M operatesfto restore switch W to its normal position. Operation of switch W under the above conditions is maintained 'until' the switch reaches its full normal position, whereupon contactl-S of controller J is opened to interrupt the circuit of the main winding of relay Relay NWR then releases to open the last traced circuit of motor M and thereby terf minate operation of the switch.

It should be pointed out that reset winding 25 of relay ROB becomes energized when motor M is controlled to operate switch W to its normal position, and as a result of thisenergization,

v v .55. terminal B through field armature 21 of relay ROR is moved from its operated position past its toggle 23 into its normal position, thereby restoring reverse overload relay ROR to its normal condition.

-It is believed that further operation of the apparatus of Fig. 1 will readily be apparent from the foregoing description together with an inspection oi the drawing, and further detailed explanation is deemed unnecessary except to point out that when the switch is being moved to its normal position by motor M, relay NOR is effective to interrupt the motor circuit in the event the switch strikes an obstruction and motor M draws excessive current. In the event that switch motor M becomes overloaded when operating to its normal position, overload winding 24 of relay NOR is then energized sufiiciently to attract its armature 2i past its toggle bias, thereby opening contact 303l, which is interposed in the previously traced circuit of main winding l8 of relay NWR, and relay NWR consequently releases to interrupt the motor circuit of motor M. When the switch lever is moved to its reverse position to control switch W to its corresponding position, relay NOR then is restored to its normal condition (wherein its contact 3ll-3I is closed) since its reset winding 25 becomes energized in series with main winding I8 of relay RWR, as was pointed out previously. It can be seen, therefore, that once an overload relay is caused to operate its armature into its operated position, the switch control lever then is removed from control of the associated switch control relay due to the fact that contact 3il3l of that overload relay is held open. After the lever is operated to establish control over the other of the switch control relays, the lever is restored to control of the first-mentioned switch control relay since contact 3ll3l of the associated overload relay then is restored to its normally closed position by virtue of the energization of its reset winding 25. It follows, therefore, that once lever E is removed by an overload relay from control of a switch operating relay, the lever can restore its control over such relay only by first establishing control over the other of the two switch operating relays.

From the foregoing, it is readily apparent that switch W may be controlled from one position to another only upon the energization of that particular one of the two switch control relays which corresponds to the position to which the switch is to be moved. It is further apparent that the proper switch control relay may be energized when and only when switch control lever E is in a position which corresponds also to the position to which the switch is to be controlled, That is to say, normal switch operating relay NWR may be energized only when lever E is in its normal position to supply current of normal polarity to relay WR and to relay NWR, and relay RWR may be energized only when lever E is in its reverse position to supply current of reverse polarity to relay WR and relay RWR. It follows from the above that improper operation of the switch, which might result when a polarized switch control relay is employed due to the vibration or jars of passing trains causing an improper reversal of the polarized contact members of the relay, is prevented by employing two polar relays which respond to different polarities of energization. In addition, it is apparent that an improper switch operating relay cannot be energized in the event that crossed wires or a ground removes switch circuit controller J- from control of the apparatus. That is to say, in the event that a wire leading from one orthe other of the switch operating relays becomes grounded and one or the other of'the switch control relays becomes energized, only that relay-corresponding to the position of the switch lever may become picked up. This results from the fact that relay NWR is picked up only on current of normal polarity and relay RWR. is picked up only on current of reverse polarity, so that improper energization of relay NWR by current ofthe wrong polarity (which might happen if polarized line relay WR is reversed due to jars or shocks of passing trains and the wires become crossed) is avoided.

Referring now to Fig. 2, a modified form of the apparatus of Fig. 1 is shown wherein a single overload relay OR of the usual type is employed. In addition, an auxiliary relay AR and a slow acting lockout relay LR also are employed.

close its reverse polar contacts 35-36 and 55-56.

Main winding l8 of reverse switch operating relay RWR. then becomes energized over a circuit which extends from terminal B through lever contact lill3, wire I5, wire 39, reverse polar contact 3535 of relay WR, wire 40, the main winding it of relay RWR, wire 4i, contact 8-! of circuit controller J l (which is operatively connected with switch W), wire 58, the winding of relay LR, wire 59, back contact 66-602) of overload relay OR, wire 6 l wire l5 and contact Hi-l2 of lever E to terminal C. Relay LR, by virtue of its slow acting characteristics, does not open its back contact 62-421) when energized until after auxiliary windings 22a and 22b of relay RWR become energized over a circuit passing from terminal B through back contact G2'52b of relay LR, wire 63, contact 64-55 of circuit controller J l (which is closed in all positions of switch W except in its full reverse position), wire 61, auxiliary windings 22b and 22a of relay RWR, wire 63 and reverse polar contact 55-56 of relay WR to terminal C. With both main winding 18 and auxiliary windings 22a and 22b of relay RWR energized, the armature of relay RWR is operated from its released to its picked up position in response to the action of the flux set up by the auxiliary windings neutralizing the hold-down effect of the main flux of relay RWR. After a sumcient time interval has elapsed to enable relay RWR to pick up, relay LR then picks up to establish an obvious circuit including the source of current and its front contact c2-'32a. for auxiliary relay AR, whereupon the latter relay picks up. With relays AR and RWR both picked up, motor M is energized with current of such polarity to cause the switch to be operated to its reverse position; the energizing circuit for motor M in this case extending from terminal B through front contact 4611-46 of relay RWR, armature winding 5 of motor M, front contact IL-I la of relay RWR, field winding 6 of motor M, the winding of overload relay OR and in parallel therewith resistor 26, and front contact 54-54a of relay AR to terminal C.

It should be pointed out that the arrangement and construction of relay RWR is such that once its armature 2 l is picked up upon main Winding l8 and auxiliary windings 22a and 22?) being energized, the armature is then held up by the energizat'ion of relay main winding 18 independently of the energization of the auxiliary windings 22a and 22b. It cah'be seen, therefore, that although auxiliary windings 22a and'zzb of relay RWR become deencrgized when relay LR picks up, relay RWR is maintained energized until such time as its main winding becomes deenergized, thereby maintaining control of motor M (unless the switch strikes an obstruction and draws excessive current to energize overload'relay OR) until the switch reaches its reverse position, At the reverse position of the switch, circuit controller contact 7-8 of circuit controller J l is opened to open the previously traced circuit of the main winding of relay RWR, with the 're'sult that relay RWR releases'to open the circuit of motor M and thereby terminate operation of the switch.

In theevent that the switch strikes an obstruction when operating to its reverse position and mo'tor'M draws excessive current so that overload relay ORibeco mes' energized, the opening of back Contact 60 '5fib0f relay OR opens the previously traced 'circuit'of main winding [8 of relayRWR, thereby causing relay RWB, to release and terminateoperatio'n oi the" switch. The opening of back contact sa est of relay OR also causes relay LR (whioh is energized in series w'ith'the main winding of relay RWR) to become deenergized. Preferably, the release period of relay LR is proportioned to bridge-the release interval of relay OR,,so that back contact Bil-Bill) of relay OR closes'to reestablish the energizing circuit of relay LR and the main .windingof relay' RWR prior to relay LRreIeasing. With the circuit of relay LR again completed; its front contact lib-62d is held closed' and as a r sult the auxiliary windings of relay remain deenergized' so that the armature of relay RWR isheld down by the main flux of its energizedwinding l8; Fur ther controlof motor Mb'yrelay RWR is, therefore, avoided at this time. I I. The switch ma'y'now be restored to its normal position moving lever E'back slowly to its normal position; the lever being held at its mid p'osie tionfwherein'its severalcontacts'are opened, for

a period slightly longer than tr ereiea e, period of relay LR. When relay-1B releases, lever E be restored to itsnormal position, and relay WR then becomes energized with current of njor till over the above on mal polarity t'o'cause that relay to close its normal polarcontacts 355 31 and 55=57, and also establish a circuit iorthejmain winding or normal switch peratin rel This circuit xtends from terminal B :through lever contact l0;l I wire l 5,' wir'e 6|, back contact 68-56111 of overload relay OB; wirefiii the' winding oi relay wire 53, contact of circuit controller Ji, wire 1 n, m m winding 18 0f reiayinwa ire '1 l, normal polar contact 35%?! of 'relay'W Wire 39, wire and contact 137M of lever Eto ter' fn'inal C. Beforev relay LR. becomes picked up euit, current is supplied to auxi iary windings 2'2 arid-122 of relay NWR over a circuitpassirigffom ter line] B through back contact 62 6211; orv relay La, wire l3, Contact ti r emanates-Bro ler; at s; r2, angina-y windings and 22d oi relay IT/VB, wire 'lli, and so e polar contact s5- -sr or re1ay we to terminai c. The cur eet suppued t windings 22a and 22b of relay NWR over the se regate; sets up neutralizing flux in relay irvva with; the

result that the armature" 2| of relay NWR is picked up., When relay LR picks up, the previously mentioned circuit of relay AR is completed,' whereupon the latter relay picks up to complete a circuit for motor M, which circuit may be traced from terminal B through front contact 59(1-69 of relay NWR,,armatur'e winding 5 of motor M, front contact ll- H0, of relay NWR, field winding 6 of motor M, the winding of overload relay OR o with resistor and front contact lid-54a of relay AR, to terminal C. The polarityof cnergization of motor M is now 26 connected in parallel therewith,

such that motor M operates to restore switch W to its normal position. its fullnormal position, J l opens to interrupt the previously traced cir- When the switch reaches edit of the main winding 01 relay NWR, with the releases *to terminate the result that relay NWR operation of motor M and switch W. o

It is believed that further operation of the ap-. paratus of Fig. 2 will readily be apparent from'the foregoing description together with an inspection of the drawing, is deemed unnecessary. I I 4 It should be noted that the apparatus of Fig. 2 provides overload protection by means of a single overload relay in a system which selectively.

energizes one or the other of the two switch operating relays in accordance of current supplied tosuch relays. It can be seen that the apparatus of Fig. 2, therefore, utilizes a minimum of apparatus to provide the utmost protection against crosses and improper reversals of the switch control relay.

Although I have herein shown and described only two forms of improved switch control systems embodying my invention, it is understood that various changes and modifications may be made therein within the scope ofthe appended claims without departing from the spirit and scope of myinvention. I

'Having thus described my invention, what I claim is: 1 i

1. In a switch control circuit, in combination, a switch control lever having normal and reverse positions, twocontrol wires, means for supplying said wires with current of normal or reverse polarity accordingas said-lever is in its normal or reverse position, a polarized relay receiving current from said wires and selectively controlled in accordancejwith the'polarity of such current, a normal and a reverse switch control relay, means controlled by said polarized relay for supplying current from said Wires to said normal or reverse relay is in its. normal or reverse, position, said normal switch control relay being arranged in such manner that its armature is operated to an energized position in response to magnetic flux set up by current of normal polarity received by the relay from said wires but is held down in its released position in response to magneticfiux set up by current of reverse polarity, said reverse switch control relay being arranged in such manner that its armature is operated to an energized position in response to magnetic flux set up by current of reversepolarity received by the-relay from said wires but is held down in its released position in response to magnetic flux set up by current of normal polarity, and switch operating means selectively controlled by said two relays.

2. In a switch controlcircuit, a switch control lever having normal and reverse positions two relays each having two windingsso arranged that the associated relay armature is operated to an energized position only when said two windings contact 1 -9 of controller and further detailed explanation with the polarity set up opposing fluxes but is retained at its released position by the flux set up when but either one of the two windings is energized or when both windings set up additive fluxes, one of said relays being arranged in such manner that its two windings set up opposing fluxes when one of its windings is supplied with current of a particular polarity and its other winding is supplied with current of normal polarity, the other of said relays being so arranged that its two windings set up opposing fluxes when one of its two windings is supplied with current of a particular polarity and its other winding is supplied with current of reverse polarity, means for supplying said other windings of said relays with current of normal or reverse polarity according as said lever is in its normal or reverse position, means controlled by said lever for supplying said one winding of said relays with current of said particular polarity, and switch operating means selectively controlled by said two relays.

3. The combination with a railway track switch reversibly operated by a switch mechanism to a position of correspondence with a switch control lever having normal and reverse positions, of two relays each having a main winding and an auxiliary winding, each of said relays being arranged in such manner that its associated armature is held to a released position by the flux created when the relay main winding is energized by current of either polarity and its auxiliary winding is deenergized, one of said relays being further arranged in such manner that when its auxiliary winding is supplied with current of a particular polarity the flux created by current only of normal polarity supplied to its main winding will operate the relay armature to its picked up position, the other of said relays being arranged in such manner that when its auxiliary winding is supplied with current of a particular polarity the flux created by current only of reverse polarity supplied to its main winding will operate the relay armature. to its picked up position, means for supplying current of said particular polarity to the auxiliary windings of each of said relays, means for supplying the main windings of each of said relays with current of normal or reverse polarity according as said lever is in its normal or reverse position, and means controlled by each of said relays for controlling said switch mechanism to operate the switch to its position of correspondence with the lever.

4. The combination with a railway track switch reversibly operated by. a switch mechanism to a position of correspondence with a switch control lever having normal and reverse positions, of two two-winding relays each arranged in such manner that its associated relay armature is held down by the flux created when but either one of its two windings is energized but is attracted to an operated position when its two windings supply flux in opposition to each other, means for at times supplying one winding of each of said relays with current of a particular polarity, one of said relays being arranged in such manner that when its one winding is supplied with current of said particular polarity itsother winding supplies opposing flux only when energized with current of normal polarity and the other of said relays being arranged in such manner that when its one winding is supplied with current of said particular polarity its other winding supplies opposing flux only when energized with current of reverse polarity, means for supplying said other windings of said relays with current of normal or reverse polarity according as said lever is position, and means controlled by each of said relays for controlling said switch mechanism to operate the switch to its position of correspondence with the lever.

5. The combination with a railway track switch reversibly operated by a switch mechanism to a position of correspondence with a switch control lever having normal and reverse positions, of two relays each having a main winding and an auxiliary winding arranged in such manner that the relay armature is operated to an energized position when and only when the relay main winding supplies flux to the relay magnetic circuit in opposition to the flux of the relay auxiliary winding, means for at times supplying the auxiliary windings of each of said relays with current of a particular polarity, one of said relays being arranged in such manner that when its auxiliary winding is energized the flux created thereby is opposed by the flux of the associated main winding only when that winding is supplied with current of normal polarity, the other of said relays being arranged in such manner that when its auxiliary winding is energized the flux created thereby is opposed by the flux of the associated main winding only when that winding is supplied with current of reverse polarity, means controlled by said lever for supplying the main windings of said relays with current of normal or reverse polarity according as said lever is in its normal or reverse position, and means controlled by each of said relays when energized for controlling said switch mechanism to operate the switch to its position of correspondence with the lever.

6. In a switch control circuit, a switch control lever having normal and reverse positions, two relays each having two windings arranged in such manner that when but either one winding is energized the associated relay armature is held down by the flux created thereby and the armature is operated to an energized position when and only when the two windings are supplied with current in such manner that the two windings set up fluxes in opposition to each other, one of said relays being arranged in such manner that its two windings set up opposing fluxes when one winding is supplied with current of a particular polarity and its other winding is supplied with current of normal polarity, the other of said relays being arranged in such manner that its two windings set up opposing fluxes when one winding is supplied with current of a particular polarity and its other winding is supplied with current of reverse polarity, means for supplying said other windings of said relays with current of normal or reverse polarity according as said lever is in its normal or reverse position, means controlled by said lever for supplying current of said particular polarity to said one winding of said relays, and switch operating means selectively controlled by said two relays.

7. In a switch control circuit, a reversible electric motor for reversibly operating a railway track switch, two overload relays each having an overload and a reset winding, said relays each having a first armature controlled by its overload winding from its normal position to its operated position and biased to its last occupied position, said relays each having a second armature controlled by its reset winding, said relays each including means controlled by its second armature for restoring said first armature to its normal pcin its normal or reverse sition, circuit means including the overload wind- 1 ing of one of said two relays and the reset winding'of the other of said relays for causing said motor to operate in one of its directions, and circuit means including the overloadwinding of said other relay and the reset winding'of said one relay for causing said motor to operate inthe other direction. 1

8. In a switch control circuit, a switch control lever having normal and reverse positions, two relays each having two windings and each caused to be operated to anenergized position-when and only when its two windings set up opposing fluxes, said relays being arranged in such manner that when one Winding of one of said relays is supplied with current of normal polarity or when one Winding of the other of said relays is supplied with current of reverse polarity opposing fluxes are set up in the relay when the other windings of said relays are supplied with current of a predetermined polarity, means for supplying current of normal polarity to the one winding of said one relay or current of reverse polarity to the one winding of said other relay according as said lever is in its normal or reverse position, a slow acting relay connected in circuit with said one winding of each of said relays, means controlled by said slow acting relay when released for supplying current of said predetermined polarity to said other winding of each of said relays, a reversible electric motor for selectively operating a railway track switch, means controlled by each of said two relays for selectively controlling said motor, an overload relay responsive only to excessive current drawn by said motor, and means controlled by said overload relay and interposed in circuit with said one winding of each of said relays whereby to cause the deenergization of said windings to remove said relays from control of said motor, said slow acting relay having a release period sufficient to bridge the picking up and releasing of the overload relay in the event that said motor draws excessive current.

CLARENCE W. DALZELL. I 

